Color photography.



Patented Apr. 2, 1918.

F. E. IVES.

COLOR PHOTOGRAPHY.

APPLlcAUoNJILED1uLY19.1916.

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FREDERIC EUGENE IVES, OF PHILADELPHIA, PENNSYLVANIA.

COLOR PHOTOGRAPHY.

To all whom it may concern:

Be it known that I, FREDERIC E. IvEs, a citizen of the United States,residing at Philadelphia, in the county of Philadelphia v photography,and more particularly to a novel color photography plate-pack, that is,a prearranged set or group of sensitive plates or` ilms, and to a methodof preparing the same. l

' While the present improvement might be otherwise applicable, it isparticularlyintended for the three-color system, and it is moreespecially directed to the object of enabling photography' in thethree-color sys? tem to be practised with the ordinary camera orplate-holder. A suitably designed platepack, made on the principles ofthis invention, may be used in various ways in the plate-holder orcamera; and by plate-pack I include any convenient set or groupof'plates or films adapted to the Apurposes hereof.

When in proper place in the plate-holder or camera the pack may beexposed for 'the proper length of time, with or without theinterposition of suitable color screens.

vExamples of plate-packs for the trichromatic or three-color system ofcolor photography yare illustrated in my prior Patents Nos. 927,244 ofJuly 6,1909, and 1,178,429 of February 29, 1916. v Insaid priorv patentsa member or layer sensitive to one color (green) is located between afront member or layer sensitive to another color (blue) and a rearmember or layer sensitive to the third color (red), the several memberswith their -supports being held snugly togetherin the form of aplate-pack. By. this arrangetive of the camera through the severaltransparent, sensitive, closely contacting layers form images upon all of themy in a single exposure. f

The details of the `plate-packs described in my said prior patents maybe ascertained from the patents. I will describe the plate-,Specification of Letters Patent.

' .Implication filed July 19, 191s.

Patented Apr. 2, 1918. Serial No. 110,041.

pack constitutingthe present invention and themethod of making the samewith particular referenceto the features of improvement and noveltyconstituting the present invention.

The general object of the present invention having been above stated,particular objects may bereferred to as consisting in improving theefficiency, accuracy, ease of building-up, compa-ctness and ease oftreatment after exposure. Other and more detail objects and advantageswill be elucidated in the hereinafteitfollowing description or will beapparent to those skilled in the art.

' To the attainment of the abovereferred to objects, the presentinvention consists vin the ,novel color-photography plate-'packhereinafter described and illustrated, and the novel components thereof,and the method of makin the same.v

.1 n the accompanying drawings forming a part hereof, Figure l is asectional View of a number of components ,shown in their.

proper -order to constitute ,a p1ate-pack 'ac cordi'ng lto thisinvention, but slightl separated and much exaggerated to ren erfthe-illustration and description more lucid.

`and 4 respectively.\ The fmembei` 2 is redsensitive, the member 3green-sensitive and the' member 4 blue-sensitive in the preferredembodiment of the invention, but, as changes in actual colors arepossible, these may confront should' be r1 which could be held ytogetherunder clamping pressure.

or safety and exclusion of light the rear of the plate-pack should beopaque or coated v 9o veniently be referred to as the rear color,

to exclude admission'of light, whereas the front of the packl and theintermediate layers must be transparent to permit the pene- .tration ofrays to the rearmost sensitive member. l

'The red-sensitive member 2 preferably comprises a transparent carrier6, which may be of glass and rigid, as in Figs. 1 and 2, or of celluloidand iexible, as in Figs. 3 and 4, in which latter case a separate opaquepadr or plate 5 may be applied at the rear for clamping purposes. Facingforwardly or at the front surface of the'carrier 6 is the red-sensitivecoating 7. It will be understood that this is a specially sensitizedlayer, and, although not insensitive to blue and green light, no -blue.light can reach it through the two forward components to'be described,while so little green can reach it, as t6 be practically negligible; ora red' surface stain applied on or in front of the layer7 willcompletely exclude undesirable v light.

Referring next to the green-sensitive member 3, this comprises at therear side the green-sensitive coating 9, formed'on a preferably flexiblecelluloid carrier 10. At

`the front of this celluloid carrier is indicated a colloid layer orbacking 10a, the purpose of which will nowbe explained.

The intermediate celluloidflayer 10 is preferably of extreme thinness,so as to occupy as little space as`4 possible in the plate-pack andavoid separating the contacting red and green sensitive layers from theblue-sensitivelayer any more than necessary. lt has been foundy thatwhen the f green-sensitive emulsion has been applied t0 one side of thincelluloid, the uncovered side, by reason ofthe volatilization of one ormore of its constituents, shrinks somewhat, although slowly, and, whenkept in packages, shrinks fastest lat the exposed edges, thus bucklingthe .film and making 1t unsuitable for this purpose. Moreover, if suchshrinkage occurs after the film is exposed and-converted into anegative, such shrinkage, even if not uneven, destroys'the register ofthe images by making the greenlight negative smaller than'those onglass. This defect I have discovered may be eliminated by employingcelluloid which has been. coated, or is in .adhering contact, with agelatin film on both sides. Gelatin is prac tically impervious to thecamphor or other volatlle constituents of celluloid film, and

thus is able to prevent .the shrinking and' buckling `referred to.

Instead. of coating the front surface of the carrier 10 with a specialgelatin layer 10a 'as described, the "same result may be ob- A tained,as indicated in Fig. 4, by the adhering attachment of the celluloid tothe colloid surface of the blue-sensitive member 4 of celluloid orflexible, as

at the front. This is readily effected by.

by applying a gelatin coating to the nished negative. Referring now t`othe front or blue-sensitive member 4, this consists of the blue-sensi-ytive coating 12 at the rear side of the transparent carrier 13, whichmay be of glass or rigid, as seen in Figs. 1 and 2, or may be in Figs. 3and 4, in which latter case .a separate rigid glass plate 14 may beapplied at the front for flatly clamping the entire plate-pack duringexposure'.

Another respect to said prior patents this was a relatively finegrainedand very transparent layer, so -as to reduce the actinic action andassist in securing the proper relative exposures for the three' featureof improvement is with members, and to transmit the red and green raysfreely and with minimum scattering and diffusion. Withsuch ablue-sensitive layer it became necessary to prevent trans'- mitted bluelight from reaching the sensitive emulsions to the rear. For thispurpose a superficial yellow color screen coating was applied to therear of, and preferably directly upon, the blue-sensitive layer.

A defect, however, has been found in 'jplate-packs made according to myprior patents. Owing to the great transparency of the blue-sensitivelayer, consisting of sil- 'ver salt contained in a colloid emulsion, the

4actinic effect of the light extended entirely through the depth of thelayer to the rear surface in such way that, although the relativegradations were well enough preserved at each point on thev plate, thedensity of the resulting negatives in the most exposed porltions variedperceptibly. rlhis was; found to be due to variations of the thicknessof the sensitive emulsion coating itself. It is practically I impossiblein the commercial manufacture of photographic dry plates to avoid someunevenness of coating due to the` unavoldable variatlons in the trueneof' the glass surface.

My improvement for overcoming this defect 1s to adopt a means toequalize the acthe blue-sensitive layer 12. In y tion of the light overall portions of the y plate. This I have succeeded in accomplishing byincorporating in the blue-sensitive layer an amount of soluble dyeof.non actinic color suicient to limit the effective penetration of theblue light, so as to confine its action practically to the underneath orforward portion of the sensitive layer or to such thickness thereof asis represented by the thinnest parts of the variable coating,

lA yellow dye such as tartrazine is entirely suitable for this purpose.Its incorporation in the emulsion or in the sensitive layer effects theretardation of light for the purposes referred to.

. Furthermore, it will be observed that this yellow coloring matter willserve not only to thus equalize the action of light in an unevenlycoated film, but also as a color screen to exclude the blue rays fromthe green and red-sensitive members behind,l It thus serves differentfunctions including that of the superficial in said prior patents.

Another advantage or function of this part .of my improvement isthat itpermits the effective speed of a blue-sensitive plate to be reducedquantitatively, which is highly desirable to place it on equality withthe other' plates; and gives correction, as well, ofthe characteristlctendency of such slow plates to relatively excessive contrast anddensity.

K The non-actinic dye, actingas a restrainer, thus insures reduction indensity and contrast as well as equalization of action, and control ofspeed, and, in practice, these functions and benefits cordinate so thatno one is gained at the sacrifice of any other function.

. Furthermore, this improvement permits the usual yellow compensatingscreen to be omitted from the camera. This was employed to equalize theaction of the light on the three sensitive members. The reduction by thelight restrainer in the bluesensitive member effects this function.

This improvement, therefore, perfects the action of the film packs ofthe prior patents in several ways. The characteristics of theblue-sensitive members are rendered such'- as to bein close agreementwith those of the other sensitive members of the plate-pack. The use ofa color which, like tartrazine, cuts off 'the blue-violet spectrumrays,I to which the fine-grained blue-sensitive plates are aloneresponsive, without any reduction of the green'or red lighttransmission, substantially equalizes any possible inequalities ofopacity due to varying thicknesses of the blue-sensitive coating. rlhecordination of all lthe factors mentioned by the simpleimprovement-recited is remarkably successful in' practice,

The green-sensitive member may .be somewhat improved by incorporatingyellow tartrazine dye, and the red-sensitive member may be similarlyimproved by incorporating a yellow rhodamine dye in the emulsion;

these improvements giving complete assuryellow layer employed group ofspectrum rays.

It will be seen that according to this invention all three of thesensitive members may be flexible, because including celluloid carriers.By this arrangement the further advantage is attained that two. or moreof the members, for example, the red-sensitive member 2 and thegreen-sensitive member 3, may be produced from the same batch, and maytherefore be of corresponding qualities. Thus, a batch ofgreen-sensitive members may be constructed from a given emulsion and aportion of them converted to red-sensitiveness in accordance with saidprior Patent 1,173,429. This insures the same density and gradationfactors for both of these members. Moreover, the greater flexibility andevenness of the Celluloid film, as compared with glass plates, wouldgive a greater assurance of perfectly even contact. An elastic pad 5 atthe rear as a clamping member opposed to the transparent glass at thefront enhances intimate contact.

It will thus be seen that I have described a plate-pack, and indicatedthe process -of lmaking the same, which accomplishes the' 'with aninterposed green-sensitive member facinv the red-sensitive member, saidblue- 4sensitlve member havin its sensitive coatin colored throughout1ts thickness wlth a yellow dye.

A plate-pack or plate set for color photography comprising a pluralityof differently color-sensitized photographic members secured togetherfor simultaneous.- exposure, the foremost thereof having Incorporated inits sensitized layer a non-act1n1c soluble color. t

3. A plate pack or plate set for color photography comprising a plurahtyof differcntly color-sensitized photographic me'mbers secured togetherfor simultaneous egrposure, the blue-sensitive member of. saldplate-pack having a temporary yellow dye incorporated in its sensitivelayer, whereby to restrain and equalize the light actlon therein and toserve as a color screen for the member or members Ito the rear;

el. A film pack for color photography comprising a carrier having ared-sensitive coating facing a blue-sensitive co11o1d coating on anothercarrier, with an interposed celluloid carrier having a green-sensitivecoatbers secured together for simultaneous eX? ing facing saidred-sensitive coating, `the back of said Celluloid carrier adhering tovsaid blue-sensitive coating. i

5. A plate-pack or plate set for color photography comprising aplurality of differently color-sensitized photographic mem'- posure,each of said membersl consisting of a flexible VCelluloid carrier havinga sensitized layer on one side and one of said members at its other sidebeingheld in adhering contact with the sensitized colloid face ofanother member, butpadapted to be detached for development afterexposure. ,l 6. A film pack for color photography comprising a carrierhaving a red-sensitive -coating at the rear of and facing a1bluesensitive coating on `-another carrier, with any interposedcelluloid carrier having a green-sensitive coating facing saidred-sensitive coating, said blue-sensitive coatingbeing coloredthroughout its thickness with a yellow die, -and the? back of saidCelluloid carrier being in adhering contact with said blue-sensitiveAcoating. Y

7. A film pack for color photography 'conf s isting of a plurality ofvdierentlyy colorsensitized members each comprising a carrierwith asensitive coating upon one'side only, the members being so assembledthat.

neonata the foremost and rearmost have their sensiytized surfaces facingeach other, thesensi sistav of a Celluloid carrier provided Withasensitive coating upon one side, treating vthe other sideof suchcelluloid carrier with a softening agent such as amylacetate andpressing the same thussoftened into adhering contact with the sensitivevcoating 4of another ofLsuch members.

9. A lm pack for color photography coinprising a redsensitive member atthe rear.v

of and facing a blue-Sensitive member, with an interposedgreen-sensitive member facing the red-sensitive member,

sensitive member having its coating colored throughout with,+ a yellowfdye, and said -green-sensitive member comprising a transparent carriervbearing-a colloid coating at its side facing the blue-sensitive member.

ln testimony whereof, l have afxed my Isignature thereto. f

i' FREDERllC EUGENE llVES.

said bluei

